The Environmental Protection Agency estimates that vehicles using natural gas can reduce carbon-monoxide emissions by more than 90 percent.

“This is part of a national trend that we’re starting to see develop,” says Chanda Felder, parking commercial development manager for the Houston Airport System. “Natural gas is an inexpensive, cleaner fuel source, that’s readily available here in the United States, and I’m just thrilled to see the City of Houston play such a leading role in this type of green initiative.”